Apparatus and method for producing metals of improved quality.



H. M. CHANCE. APPARATUS AND METHOD FOR PRODUCING METALS 0F IMPROVED QUALITY. APPLICATION ElLED JUNE 12. 1916.

1,221,139. Patented Ap. ,1917.

2 SHEETS- A4 Maw, 1mm

H. M. CHANCE.

APPARATUS AND METHOD run PRODUCING METALS 0F MPROVED QUALITY.

APPLICATION FILED JUNE 12 l9l6.

1,221,139. Patente r. 3, 1917.

1%, m 0AM UNITED STATEES PATEIYT OFFICE.

HENRY M. CHANCE, OF PHILADELPHIA, PEI INSYLVANIA.

Specification of Letters Patent.

Patented Apr. 3, 1917.

Application filed June 12, 1916. Serial No. 103,170.

To all whom it may concern:

Be it known that I, HENRY M. CHANGE, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented a new and useful Apparatus and Method for Producin Metals of Improved Quality, whereof t e following is a specification.

My invention consists of apparatus and method of operating same for producing metals of improved quality by utilizing the action of an electric current in conjunction with the reduction of metals from their ores. The use of electrolysis for reducing metals from a fused electrolyte is known and the use of electrolysis in connection with a fused electrolyte for the refining or purification of metals is also known. One of the difficulties in refining metals by such processes is found in the cost of fusing and maintaining the metal and fused electrolyte at the temperature necessary for carrying on the process.

My invention relates to apparatus and method whereby the reduction of ore by fuel (i. e., the production of metal) and the refinin of the meta-l by means of reactions induced or produced by an electric current are combined.

In carrying out my invention, a more desirable result however may often be obtained than would be possible with a process which merely combines the production of the impure metal and the refining of the metal by removal of the impurities, because in many cases the passing of the electric current through the fused materials may prevent the metal from absorbing or uniting with impurities that otherwise would find their way into the fused metal. The effects of the op eration therefore may be preventive or-cor rective or both.

My invention provides a method for operating iron blast furnaces, whereby the advantages of thermal and chemical reduction are combined with those of electrolytic purification, thus securing at relatively low cost the production of high-grade pig iron or pig steel; but while it is especially adapted to this particular use it may also be applied to blast furnaces smelting the ores of other metals.

To attain these ends I provide a source of electric current and by means of suitably connected conductors I cause this current to pass through tie slag bath and molten metal (with which the slag is in contact) which is contained in the crucible of a blast furnace to which my invention is to be applied.

Some forms of apparatus for carrying out my invention are illustrated diagrammatically by the driwings, in which Figure I is a vertical cross section of a blast furnace of standard type, Fig. II is a similar section of the lower part of a modification of such a blast furnace, and Fig. III is a similar crosssection of the lower part of another modification of such a furnace which has been provided with a dam separating that part of the crucible below the slag tap into two parts, each of which is provided with a metal tap hole. In the several drawings like numerals indicate like parts.

In the drawing Fig. I, 1 indicates the shaft wall of the furnace, equipped with charging hell 9, 3 indicatesthe bosh of the furnace, 4 the blast twyers, 5 the crucible of the furnace provided with a slag tap 6 and metal tap 7. One or more conductors, or electrodes, 8, project through the furnace wall and are electrically connected by conductors 11 through a source of electric energy 9 (shown as a generator, but intended conventionally to represent included switches, resistances and accessories commonly connected with and used in controlling and operating generators of electric energy) with a conductor or electrode 10, which passes t irough' the wall of the crucible 5 and thus is in electrical contact with any metal cont lined in said crucible.

The operation of the method when smelting material su :11 as iron ore is as follows:

Assuming t: 1e furnace to be charged through bell 2 with a mixture of iron ore, coke and limes ;one, and the charge to have been ignited, ",he blast through twyers 4 effects the combustion of the fuel, and the reduction of the ore to metal and the fusion of the metalli: iron proceeds as in blast furnaces of ore inary type; the slag and the molten iron collect in the crucible 5 and are tapped ort periodically through the sla ta 6 and metal tap 7.

n e ectric current is passed through the slag and molten metal by means of the electrode 8, source of electric energy 9, elec- .stances of the substances thus affected.

trode 10, and the conductors 11. This current flows by conduction through the furnace charge (which fills the shaft and bosh of the furnace and which thus becomes an electrode or conductor of great cross-sectional area) and may flow both by comduction and electroylsis through the zone of fiuid slag. A portion of the current may also pass by coiiduction from the electrode 8 through the furnace wall 1 to the slag in the crucible 5 when under the conditions of operation the electrical resistivity of the brick lining, which may be more or less coated with slag, becomes relatively small.

Under the conditions thus produced the furnace charge becomes an electrode or pole piece-in contact with the fused slag, and the fused metal likewise becomes an electrode or pole piece in contact with the slag, so that electrolytic decomposition of the reagent or reagents of the slag most easily electrolyzed will be produced or will tend to be produced, and will be manifested by changes in chemical composition or in relative chemical affinities at the two regions of contact between the two electrodes and the sla T he component or components of the reagent or -reagents thus affected at these regions of contact will unite chemically with materials of the electrode for which such component or components have relatively high chemical afiinity. In some cases the tendency to such chemical union will be increased by the nascent condition of the elec trolyzed substances, and perhaps also in some cases by electrolysis or a tendency to electrolysis of some of the materials of which the electrodes consist.

While it is not a primary object of my invention to use the electric current, (as in electric furnaces used for the reduction of metal from their ores) to produce a high temperature for the purpose of accelerating the reduction of ores to metal, some heat will (incidentally) be produced by the elec trical resistance of the materials through which the electric current is passed, but if the cross-sectional area is large this electrical resistance usually will be relatively small and the heat thus produced will be relatively small, most of the electric energy consumed under these conditions being used to secure electrolytic and chemical effects upon components of the slag and to promote the union or combination with other sub- It should however be noted, that in operating my invention it may sometimes be desirable to utilize electric heating effects to increase the temperature of the fused materials in order to accelerate the electrolytic and chemical reactions, to keep the slag and metal in a highly fluid state, or to perform either or both of these functions.

It should also be stated that While the [low of electric current through the electrodes (where the electrodes comprise the furnace charge and the molten metal) in some cases may be wholly by electric conduction, a tendency to electrolytic decomposition of substances contained in or forming a part of either electrode may often be an important factor in acceleratin the de sired removal of impurities from t e metal, in preventing the contamination of the metal by such impurities, in retaining the impurities in the slag and in preventing them from rentering the metal bath.

Metals produced by the smelting of ores in blast furnaces usually contain appreciable percentages of impurities derived from the ores or fluxes or fuel used in smelting. The impurities become mixed or combined with the metal at or during its reduction, or at or durin its fusion, or are absorbed from the body of fused slag or cinder that is in contact with (and usually is floating upon) the fused metal.

Some of these impurities may be advantageous and can profitably be retained.

When the slag produced in smelting contains a reagent or reagents, capable of electrolytic decomposition, and containing a component or components having relatively high chemical afiinity for an impurity or impurities contained in the metal, electrolysis of the slag will provide conditions favorable to the removal of the impurity from the molten metal, by the chemical union of such component and such impurity, the resulting product mixin with, difi'using into, or being absorbed by the slag, or (if volatile) being driven off as gas or vapor.

If the sla produced in smelting does not contain sue a substance capable of electrolytic separation, then such substance may be added to provide a. slag which shall contain it.

The operation of my invention by the apparatus shown by Fig. II will be understood from the description of the operation of that shown by Fig. I. In this Fig. II the electrode or pole-piece 8 is located in the wall of the crucible 5 at or about the level of the slag tap 6. When so located it is in direct contact with slag contained in the crucible 5 and the current passes directly from the electrode 8 to the slag and does not pass through the charge filling the furnace as in Fig. I.

The drawing Fig. III shows a modification of the crucible of a blast furnace of standard type by the addition of a wall 12, which may be provided with perforations for circulating a cooling medium, by which the crucible 5 is divided into two halves, each provided with a tap hole for metal 13, 13. This wall 12 extends upward from the bottom of the crucible 5 to a point at or below the level of the slag tap hole 6 so that in tapping off slag the slag will not be drawn down below the top of this wall. Two electrodes 14: and 15 pass through the base of the crucible 5 to connect with each of the two compartments into which the lower part of the crucible is divided by the wall 12. These two electrodes 14 and 15 are electrically connected through a source of electric current 9 by the conductors 11. By this arrangement the fused metal in each compartment of the crucible becomes an electrode or pole-piece in contact with the slag and current will flow through the slag from one electrode to the other. The metal from the two compartments of the crucible may be tapped out alternately, and if a direct current be used the electrolytic action may be reversed by reversing the current.

In providing a slag that will have the properties which have been described above as desirable in the operation of the apparatus and method above described, electrolyzable compounds of the alkali and alkaline earth metals (not volatile at the temperature used) are among the most generally useful substances for these purposes, because these metals have relatively high chemical affinity for many of the non-metallic impurities contained in pig iron and other crude metals.

The term blast furnace as used in the specification and claims hereof is intended to mean that type of shaft furnace in which a mixture of ore, flux and carbonaceous fuel introduced into the furnace stack is smelted by the combustion of said fuel produced by a blast of air, oxygen or mixture of air and oxygen, introduced adjacent to the slag zone of said furnace and at or below the zones of reduction and of fusion of said furnace, and the term blast as used in the specification and claims hereof is intended to mean such blast of air, oxygen or mixture of air and oxygen.

Having thus described my invention, I claim:

1. Apparatus for producing metals comprising in combination a blast furnace, means whereby ore, flux and fuel may be introduced into said furnace, means for supplying air for combustion of said fuel, means for removing the reduced metal and the slag from said furnace, and means for passing an electric current through fused slag contained in said furnace.

2. Apparatus for producing metals comprising in combination a blast furnace, means whereby ore, flux and fuel may be introduced into said furnace, means for supplying air for combustion of said fuel, means for removing the reduced metal and the slag from said furnace, and means for passing an electric current through fused slag and metalcontained in said furnace.

3. Apparatus for producing metals comprising in com bination a blast furnace, means whereby ore, flux and fuel may be introduced into said furnace, means for supplying air for combustion of said fuel, means for removing the reduced metal and the slag from said furnace, and means for passing an electric current through material of the charge, through the fused slag and metal contained in said furnace.

4. Apparatus for producing metals comprising in com bination a blast furnace, means whereby ore, flux and fuel may be introduced into said furnace, means for supplying air for combustion of said fuel, means for removing the reduced metal and the slag from s mid furnace, and means for passing an electric current through fused slag contained in said furnace, said means consisting of a S)III'CB of electric energy electrically connected to pole-pieces or electrodes which provide electrical contact with materials withirv said furnace.

5. The impro ement in blast furnace construction which consists in the combination with said furnace of a source of electrical energy and conductors electrically connected through sucl. source with terminal electrodes adapted to insure the passage of electric current from said source through fused slag and metal contained in said furnace.

6. The method of operating blast furnaces which consists i1 introducing into said furnace ore, flux a1 vd fuel, in supplying air for the combustion of said fuel, in reducing said ore by heat and by the reducing action of the fuel and reducing gases formed therefrom and in passing an electrolyzing electric current thr ough fused slag and metal contained in said urnace.

7. The method of operating blast furnaces which consists in passing an electrolyzin electric current through fused slag an metal contained in a blast furnace, in removing slag and metal and in continuing the operation of the said furnace, the passage of said current and the removal of slag and metal.

8. An improved blast furnace comprising in combination, a chamber suitable for use as a receptacle for molten metal and slag, constituting the crucible of said furnace, and provided w;.th tap holes for drawing off said molten metal and slag; a chamber superimposed upon said crucible adapted to assist in supporting the weight of any charge containel in said furnace, constituting the bosh of said furnace; a chamber superimposed upon said bosh and adapted to contain the charge to be smelted in said furnace; constituting the stack of said fur nace, and provided with charging means and means for the discharge of the furnace gases; means for the introduction of the In witness whereofIhave hereunto signed 13 blast for smelting said charge, said means my name at Philadelphia, Pennsylvania, comprising twycrs connected with a source this 10th day of June, 1916.

of blast supply and located in the upper por- 5 tion of said crucibl a and below the zones of HENRY M. CHANCE.

fusion and of reduction in said bosh and said stack; and means for passing an elec- Witnesses: trolyzing electric current through slag co11 J. H. QUINN, tained in said" furnace. CARL K. SCI-IULZE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner 0! Patents,

Washington, D. G. t 

